A key structure including a circuit board, a membrane, a positioning frame, a sensor module, a scissor leg, and a key cap is provided. The membrane is disposed on the circuit board and is electrically connected to each other. The positioning frame is disposed on the membrane. The sensor module is disposed on the membrane and is electrically connected to the circuit board. The scissor leg is connected to the positioning frame and is adapted to move up and down relative to the positioning frame. The key cap is detachably disposed at the scissor leg and is spaced with positioning frame. The key cap has a reflective plane and a shaft component. The reflective plane faces the membrane. The shaft component is extended from the reflective plane and penetrates through the scissor leg and the positioning frame to abut the membrane. The sensor module is aligned with the reflective plane.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A key structure comprising: a circuit board; a membrane disposed on the circuit board and electrically connected to the circuit board; a positioning frame disposed on the membrane; a sensor module disposed on the membrane and electrically connected to the circuit board; a scissor leg connected to the positioning frame and adapted to move up and down relative to the positioning frame; a key cap detachably disposed at the scissor leg and spaced with the positioning frame, and the key cap has a reflective plane facing the membrane, and the sensor module is aligned with the reflective plane; and a shaft component, extending from the reflective plane and penetrating through the scissor leg and the positioning frame to abut the membrane, wherein the sensor module is adapted to detect a press stroke of the key cap relative to the membrane, and when the key cap is pressed, a digital control signal or an analog control signal is triggered through the membrane or the sensor module, wherein the sensor module comprises a light emitting device and a light detector, and the light emitting device is adapted to transmit a light source to the reflective plane, and the light source is transmitted to the light detector after the reflection, and the light detector is adapted to receive and detect the light intensity after the reflection of the light source.
2. The key structure according to claim 1 , wherein the shaft component is adapted to squeeze the membrane and to generate a deformation.
3. The key structure according to claim 1 , wherein the positioning frame has a plurality of hook portions, and the key cap has a plurality of clamp portions, and the plurality of hook portions hook up one end of the scissor leg which is away from the key cap, and the plurality of clamp portions clamp the other end of the scissor leg which is away from the positioning frame.
4. The key structure according to claim 1 , wherein the key cap has a plurality of fixed portions disposed on a central position of the reflective plane, and the shaft component and the plurality of fixed portions are engaged with each other.
5. The key structure according to claim 1 , wherein the positioning frame has a plurality of holes corresponding to the reflective plane of the key cap and containing the shaft component and the sensor module.
6. The key structure according to claim 1 , wherein the scissor leg comprises an installation panel covering the sensor module, and the key cap is detachably disposed on the installation panel.
7. The key structure according to claim 1 , wherein the shaft component comprises a elastic component abutting the membrane and the reflective plane respectively and being adjacent to the sensor module, and when the key cap is pressed towards the positioning frame, the elastic component is driven a generate non-linear deformation.
8. The key structure according to claim 7 , wherein an initial value of a press stroke of the key cap relative to the membrane is 2.2 mm.
9. The key structure according to claim 1 , wherein the shaft component comprises an elastic component abutting the membrane and the reflective plane respectively and being adjacent to the sensor module, and when the key cap is pressed towards the positioning frame, the elastic component is driven to generate a linear deformation.
10. The key structure according to claim 9 , wherein an initial value of a press stroke of the key cap relative to the membrane is 2.8 mm.
11. A mode switching method comprising: a key structure comprising: a circuit board; a membrane disposed on the circuit board and electrically connected to the circuit board; a positioning frame disposed on the membrane; a sensor module disposed on the membrane and electrically connected to the circuit board; and a scissor leg connected to the positioning frame and adapted to the move up and down relative to the positioning frame; disposing a first key cap having an elastic component at the scissor leg, making the elastic component abut the membrane to prepare for a digital mode; when pressing the first key cap, the elastic component generates a non-linear deformation to squeeze the membrane to further trigger a digital control signal; replacing the first key cap having the elastic component with a second key cap having an elastic component, making the elastic component abut the membrane to prepare for an analog mode, wherein the second key cap has a reflective plane facing the membrane, and the sensor module is aligned with the reflective plane; and when pressing the second key cap, the elastic component of the second key cap generates a linear deformation to trigger an analog control signal through the sensor module detecting the change of a press stroke of the second key cap relative to the membrane.
12. The mode switching method according to claim 11 , wherein the sensor module comprises a light emitting device and a light detector, and the light emitting device is adapted to transmit a light source to the reflective plane and the light source is transmitted to the light detector after the reflection, and the light detector is adapted to receive and detect the light intensity of the light source after the reflection to calculate the press stroke of the second key cap and to transform the light intensity into the corresponding analog control signal.
13. The mode switching method according to claim 11 , wherein while in the analog mode, the sensor module sets a middle value, and when the press stroke of the second key cap relative to the membrane is greater than the middle value, an OFF signal is triggered, and when the press stroke of the second key cap relative to the membrane is smaller than the middle value, an ON signal is triggered.
14. The mode switching method according to claim 11 , further comprising turning off the sensor module after disposing the first key cap having the elastic component at the scissor leg.
15. The mode switching method according to claim 11 , wherein turning on the sensor module after replacing the first key cap with the second key cap.
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March 14, 2019
July 14, 2020
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